Cancer serum index and prostatic acid phosphatase for detection of progressive prostatic cancer

Glycoproteomic analysis of prostate cancer tissues by SWATH mass spectrometry discovers N-acylethanolamine acid amidase and protein tyrosine kinase 7 as signatures for tumor aggressiveness

The identification of biomarkers indicating the level of aggressiveness of prostate cancer (PCa) will address the urgent clinical need to minimize the general overtreatment of patients with non-aggressive PCa, who account for the majority of PCa cases. Here, we isolated formerly N-linked glycopeptides from normal prostate (n = 10) and from non-aggressive (n = 24), aggressive (n = 16), and metastatic (n = 25) PCa tumor tissues and analyzed the samples using SWATH mass spectrometry, an emerging data-independent acquisition method that generates a single file containing fragment ion spectra of all ionized species of a sample. The resulting datasets were searched using a targeted data analysis strategy in which an a priori spectral reference library representing known N-glycosites of the human proteome was used to identify groups of signals in the SWATH mass spectrometry data. On average we identified 1430 N-glycosites from each sample. Out of those, 220 glycoproteins showed significant quantitative changes associated with diverse biological processes involved in PCa aggressiveness and metastasis and indicated functional relationships. Two glycoproteins, N-acylethanolamine acid amidase and protein tyrosine kinase 7, that were significantly associated with aggressive PCa in the initial sample cohort were further validated in an independent set of patient tissues using tissue microarray analysis. The results suggest that N-acylethanolamine acid amidase and protein tyrosine kinase 7 may be used as potential tissue biomarkers to avoid overtreatment of non-aggressive PCa.

The usefulness of serum acid phosphatase in monitoring patients with advanced prostate carcinoma

The usefulness of serum acid phosphatase (SAP) in monitoring patients with advanced prostate carcinoma has been questioned. We reviewed a series of 59 patients with stage D2 prostate carcinoma. All patients had extended follow-up through at least one clinical relapse, or death. Responses to a variety of therapies were characterized as absent, subjective, or objective. All patients with an elevated pre-treatment SAP that fell to normal following therapy had prolonged survivals and improved prognoses. Conversely, all patients with an elevated SAP which did not normalize following therapy had poorer survivals. Among 36 objective responses to therapy, the SAP was elevated prior to or simultaneous with disease progression in 33 (93% sensitivity). In each ease where the pretreatment SAP normalized following therapy, any subsequent elevation in SAP above normal was always associated with clinical evidence of disease progression (100% specificity). Changes in SAP following therapy correlate well with both disease regression and disease progression in patients with advanced prostatic carcinoma.

Synthesis of alpha 1-acid glycoprotein by the human prostate

In order better to define the extent of protein synthesis capacity of the human prostate, we have studied the translation of selected serum proteins using isolated poly(A)+ RNA preparations and the rabbit reticulocyte lysate system. The translation of alpha 1-acid glycoprotein could be conclusively demonstrated but there was no apparent translation of albumin and plasmatic transferrin. Labeled alpha 1-acid glycoprotein was identified by specific immunoprecipitation with a commercial anti alpha 1-acid glycoprotein antiserum and correct processing by canine pancreatic microsomal membranes. Furthermore, we have shown by the immunoperoxidase technique that alpha 1-acid glycoprotein was indeed localized mainly in prostatic epithelial cells in 2 out of 2 patients with benign prostatic hypertrophy and in 3 out of 11 patients with prostatic adenocarcinoma. The significance of the synthesis and secretion of alpha 1-acid glycoprotein by prostatic cell themselves is presently unknown. However, we think that it could represent an interesting subject to explore further in relation with prostatic inflammation.

Orosomucoid:prealbumin ratio--a marker of the host-tumor relationship in head and neck cancer

The OPR was studied in 203 patients with squamous cell carcinoma of the head and neck at the time of diagnosis, before any specific treatment. The mean initial OPR value was significantly higher in cancer patients than in 63 healthy controls: 5.29 +/- 3.09 vs. 2.63 +/- 1.07; P less than 0.001. There was no significant difference by anatomic site, but the OPR was significantly lower in stage I-II disease than in stage III-IV: 5.10 +/- 3.85 vs. 3.23 +/- 1.99, P less than 0.001. An initial OPR under or over 6 seems to be an important prognostic factor: at 2 years, 51% of patients with an OPR less than 6 were alive vs. only 24.5% of those with an OPR greater than 6, P less than 0.001. The difference was also noted in patients with stage III-IV disease (mean survival: 16 months vs. 7 months, P less than 0.001) and in 89 of the patients who received chemotherapy (mean survival 16 months vs. 6 months, P less than 0.001) whatever the response to chemotherapy. The OPR index, which explores nutritional and acute phase reactant proteins, seems to reflect the host-tumor relationship. Its initial value is strongly related to prognosis at 2 years.

Methods of early diagnosis in genitourinary cancer

The commonly employed methods for the early detection of urologic cancers remain the traditional techniques of a carefully performed history and physical examination. Newer developments include, among others, prostate-specific antigen and monoclonal antibodies in prostate cancer, flow cytometry in bladder cancer, computerized axial tomography (CAT) scanning in renal cancer, and ultrasound in testicular cancer. These and other new diagnostic techniques, with further testing and wider use, will hopefully permit the earlier diagnosis of genitourinary cancer.

Biochemical monitoring of carcinoma of prostate treated with an LH-RH analogue (Zoladex)

The levels of prostatic specific antigen (PSA) and prostatic acid phosphatase (PAP), both measured by radioimmunoassay, and two cancer indices given by the ratio of serum alpha-1 acid glycoprotein to prealbumin (AGP:Palb) and alpha-1 acid glycoprotein to alpha-2 HS globulin (AGP:HS) were evaluated as markers to assess the response of prostatic cancer to treatment with Zoladex, an LH-RH agonist. A rise in PSA and PAP occurred in 8/65 patients (12%) during the initial induction phase. In metastatic disease prior to treatment none of these indices was significantly different between patients who attained a sustained response and those whose response was nil or only transient. Responders and non-responders could, however, be distinguished by the levels of various analytes after treatment. At 6 months the median PSA in those who responded was 2.5 ng/ml compared with 51.5 ng/ml in the non-responders. At 12 months the figures were 3.0 and 155 ng/ml respectively. The corresponding median PAP levels were 1.4 and 19 ng/ml at 6 months and 1.3 and 18 ng/ml at 12 months. The AGP:Palb ratio was also significantly different in these two groups at 6 and 12 months. PSA appears to be the most sensitive indicator of the response to treatment. The likelihood of obtaining a prolonged clinical response can be assessed within 6 months of the start of treatment.